mm: add vm_insert_mixed
vm_insert_mixed will insert either a raw pfn or a refcounted struct page into
the page tables, depending on whether vm_normal_page() will return the page or
not. With the introduction of the new pte bit, this is now a too tricky for
drivers to be doing themselves.
filemap_xip uses this in a subsequent patch.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Jared Hulbert <jaredeh@gmail.com>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/memory.c b/mm/memory.c
index c5e88bc..bbab1e3 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1176,8 +1176,10 @@
* old drivers should use this, and they needed to mark their
* pages reserved for the old functions anyway.
*/
-static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
+static int insert_page(struct vm_area_struct *vma, unsigned long addr,
+ struct page *page, pgprot_t prot)
{
+ struct mm_struct *mm = vma->vm_mm;
int retval;
pte_t *pte;
spinlock_t *ptl;
@@ -1237,17 +1239,46 @@
*
* The page does not need to be reserved.
*/
-int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page *page)
+int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
+ struct page *page)
{
if (addr < vma->vm_start || addr >= vma->vm_end)
return -EFAULT;
if (!page_count(page))
return -EINVAL;
vma->vm_flags |= VM_INSERTPAGE;
- return insert_page(vma->vm_mm, addr, page, vma->vm_page_prot);
+ return insert_page(vma, addr, page, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_insert_page);
+static int insert_pfn(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn, pgprot_t prot)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ int retval;
+ pte_t *pte, entry;
+ spinlock_t *ptl;
+
+ retval = -ENOMEM;
+ pte = get_locked_pte(mm, addr, &ptl);
+ if (!pte)
+ goto out;
+ retval = -EBUSY;
+ if (!pte_none(*pte))
+ goto out_unlock;
+
+ /* Ok, finally just insert the thing.. */
+ entry = pte_mkspecial(pfn_pte(pfn, prot));
+ set_pte_at(mm, addr, pte, entry);
+ update_mmu_cache(vma, addr, entry); /* XXX: why not for insert_page? */
+
+ retval = 0;
+out_unlock:
+ pte_unmap_unlock(pte, ptl);
+out:
+ return retval;
+}
+
/**
* vm_insert_pfn - insert single pfn into user vma
* @vma: user vma to map to
@@ -1261,13 +1292,8 @@
* in that case the handler should return NULL.
*/
int vm_insert_pfn(struct vm_area_struct *vma, unsigned long addr,
- unsigned long pfn)
+ unsigned long pfn)
{
- struct mm_struct *mm = vma->vm_mm;
- int retval;
- pte_t *pte, entry;
- spinlock_t *ptl;
-
/*
* Technically, architectures with pte_special can avoid all these
* restrictions (same for remap_pfn_range). However we would like
@@ -1280,28 +1306,36 @@
BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
BUG_ON((vma->vm_flags & VM_MIXEDMAP) && pfn_valid(pfn));
- retval = -ENOMEM;
- pte = get_locked_pte(mm, addr, &ptl);
- if (!pte)
- goto out;
- retval = -EBUSY;
- if (!pte_none(*pte))
- goto out_unlock;
-
- /* Ok, finally just insert the thing.. */
- entry = pte_mkspecial(pfn_pte(pfn, vma->vm_page_prot));
- set_pte_at(mm, addr, pte, entry);
- update_mmu_cache(vma, addr, entry);
-
- retval = 0;
-out_unlock:
- pte_unmap_unlock(pte, ptl);
-
-out:
- return retval;
+ if (addr < vma->vm_start || addr >= vma->vm_end)
+ return -EFAULT;
+ return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
}
EXPORT_SYMBOL(vm_insert_pfn);
+int vm_insert_mixed(struct vm_area_struct *vma, unsigned long addr,
+ unsigned long pfn)
+{
+ BUG_ON(!(vma->vm_flags & VM_MIXEDMAP));
+
+ if (addr < vma->vm_start || addr >= vma->vm_end)
+ return -EFAULT;
+
+ /*
+ * If we don't have pte special, then we have to use the pfn_valid()
+ * based VM_MIXEDMAP scheme (see vm_normal_page), and thus we *must*
+ * refcount the page if pfn_valid is true (hence insert_page rather
+ * than insert_pfn).
+ */
+ if (!HAVE_PTE_SPECIAL && pfn_valid(pfn)) {
+ struct page *page;
+
+ page = pfn_to_page(pfn);
+ return insert_page(vma, addr, page, vma->vm_page_prot);
+ }
+ return insert_pfn(vma, addr, pfn, vma->vm_page_prot);
+}
+EXPORT_SYMBOL(vm_insert_mixed);
+
/*
* maps a range of physical memory into the requested pages. the old
* mappings are removed. any references to nonexistent pages results